A pisco sour is an alcoholic cocktail of Peruvian origin that is typical of the cuisines from Peru and Chile. The drink's name comes from pisco, which is its base liquor, and the cocktail term sour, in reference to sour citrus juice and sweetener components. The cocktail as it is known today was invented in the early 1920s in Lima, the capital of Peru, by the American bartender Victor Vaughen Morris.
Add pisco, lime juice, simple syrup and egg white into a shaker and dry-shake (without ice) vigorously.
Add ice and shake again until well-chilled.
Strain into a chilled Nick & Nora glass.
Garnish with 3 to 5 drops of Angostura bitters.